异形催化剂组成的滴流床压强降和颗粒内扩散

Pressure Drop of Trickle Bed with Extruded Catalyst Particles and Intraparticle Diffusion

本文对异形挤条催化剂进行了颗粒传质—反应研究和滴流床床层压降的研究。压强降的研究在气液并流向下的滴流床中进行。滴流床内径为0.042m。气液系统为空气—水,空气—甘油水溶液和空气—表面活性剂水溶液。实验结果表明:三叶草形催化剂颗粒的床层压强降比圆柱形颗粒低。并得到了用小颗粒和异形颗粒床层压强降的经验关联式:用有限差分方法对颗粒内扩散—反应模型进行计算,得到了几种异形催化剂的效率因子。计算结果表明:三叶草形催化剂在化学反应中的内扩散性能大大优于圆柱形;对于内扩散控制的多相催化反应,采用异形催化剂可以显著提高表观反应速率。提出了形状对效率因子影响的估值不等式(式19)。

The mass transfer-reaction within particles and pressure drop in a trickle bed were investigated for non-cylindrical extruded catalysts.Pressure drop was investigated in a trickle bed of 0. 042 m inside diameter, using air-water, air-aqueous solution of glycerol, and air-water with surfactant as gas-liquid systems. Result shows that the three-lobal catalyst particles is lower in pressure drop than cylindrical particles. Experimental correlation was obtained by regression analysis of the data of pressure drop. In fLG = 7. 14 - 1. 24 In (z/ψ1.1 )' + 0. 074 (In (z/ψ1.1) ]2Using finite difference method, intraparticle diffusion-reaction model was calculated and effectiveness factors of four kinds of shapes of catalyst particles were obtained. Calculation results show that the three-lobal shape of catalyst is much better than cylindrical shape in diffusion behavior. When intraparticle diffusion limitation is important, the use of non-cylindrical catalyst can increase superficial reaction rate markdely. An inequality about the effect of catalyst shape on the effectiveness factor of catalyst is proposed.